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    <meta charset='UTF-8'>
    <meta name='viewport' content='width=device-width, initial-scale=1.0'>
    <title>Document</title>
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    <canvas style='border: 1px solid #ccc;' width='800' height='800' id='mycanvas'></canvas>
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<script>
    let canvas = document.getElementById('mycanvas')
    let ctx = canvas.getContext('2d')
    for (let i = 1; i <= canvas.width / 8; i++) {
        ctx.moveTo(0, 0)
        ctx.lineTo(i * 8, 0)
        ctx.lineTo(i * 8, canvas.height)
        ctx.strokeStyle = '#ccc'
        ctx.stroke()
    }
    for (let i = 1; i <= canvas.height / 8; i++) {
        ctx.moveTo(0, 0)
        ctx.lineTo(0, i * 8)
        ctx.lineTo(canvas.width, i * 8)
        ctx.strokeStyle = '#ccc'
        ctx.stroke()
    }
    ctx.beginPath()
    ctx.moveTo(80,80)
    ctx.lineTo(80,720)
    ctx.lineTo(720,720)
    ctx.strokeStyle = 'blue'
    ctx.lineWidth = 2
    ctx.stroke()

    ctx.beginPath()
    ctx.moveTo(64,96)
    ctx.lineTo(80,80)
    ctx.lineTo(96,96)
    ctx.strokeStyle = 'blue'
    ctx.lineWidth = 2
    ctx.stroke()

    ctx.beginPath()
    ctx.moveTo(704,736)
    ctx.lineTo(720,720)
    ctx.lineTo(704,704)
    ctx.strokeStyle = 'blue'
    ctx.lineWidth = 2
    ctx.stroke()
</script>

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